Gov. Henry McMaster announced Friday night a mandatory evacuation order to go into effect for the barrier islands of Colleton, Beaufort and Jasper Counties at 10 a.m. Saturday.

Those islands include Edisto Beach in Colleton County; Dafuskie Island, Fripp Island, Harbor Island, Hunting Island and Hilton Head Island in Beaufort County; and Knowles Island and Tulifinny Island in Jasper County. He said no other mandatory evacuations will be ordered, but he urged residents in those counties to consider evacuating because forecasters expect a storm surge of between four to six feet above ground level in the state’s southern-most counties on Monday.

He said he would not order lane reversals of I-26 from Charleston to Columbia, an option he was considering earlier in the week when forecast tracks pointed Irma toward the South Carolina coast. But he said that if lane reversals become necessary for the three counties under the evacuation order, local and state authorities would work together to reverse traffic as needed.

McMaster said he reviewed the 5 p.m. update to Hurricane Irma’s forecast track before making that decision.

“I need to say and need to make it clear, if we had to evacuate the whole coast starting at 10 o’clock tomorrow as we are prepared to do, we are prepared to do it,” McMaster said at an earlier news conference on Friday.

McMaster also rescinded an order of mandatory evacuations for healthcare facilities, including hospitals, nursing homes, assisted living facilities and alcohol and substance abuse treatment facilities, in Charleston, Berkeley, Dorchester, Georgetown and Horry Counties.

The order remains in effect in Beaufort, Colleton and Jasper Counties, he said.